4.8.3. Processing¶

4.8.3.1. System ¶

Available RAM (MB) : set the available RAM (in MB) that is used during the processes in order to improve the SCP performance; this value should be half of the system RAM (e.g. 1024MB if system has 2GB of RAM); in case of errors, set a value lower than 512MB;
CPU threads : set the number of threads available for processing; it is recommended to set a value lower than the maximum number of system threads (e.g. if the system has 4 available threads set value 3);

Play sound when finished : if checked, play a sound when the classification process is completed;
Use virtual rasters for temp files : if checked, create virtual rasters for certain temporary files, instead of creating real rasters; it is useful for reducing disk space usage during calculations;
Raster compression : if checked, a lossless compression (DEFLATE or PACKBITS) is applied to raster outputs in order to save disk space; it is recommended to check this option, however compressed files are sometimes larger than files without compression;
Enable writing verification : if checked, the output raster is compared to output calculation in order to avoid writing errors; it can slow the process;

SMTP server : the SMTP server to login for sending a notification email when all the SCP processes are finished (a notification is sent also in case of error, but not in case of crash);
user : the SMTP server user;
password : the SMTP server password;
Send email of completed process to : a list of addresses (separated by comma) to send the notification email to;

Some SCP tools require external programs to perform the processing.

ESA SNAP GPT executable : enter the path to the SNAP gpt executable; usually C:/snap/bin/gpt.exe for Windows, /Applications/snap/bin/gpt for Mac, and /usr/local/snap/bin/gpt for Linux; for the installation of ESA SNAP, please visit this page http://step.esa.int/main/download/snap-download/ ;
Python executable path : enter the path to the Python 3 executable (e.g. /usr/local/bin/python3); should be used only in case of issues with multiprocessing;
Python modules path : enter the path to Python modules (e.g. /Applications/QGIS.app/Contents/MacOS/lib/python3.8/site-packages); multiple paths can be entered separated by ; ; QGIS should be restarted;
GDAL installation directory : enter the path to the GDAL directory containing tools such as gdal_translate and gdalwarp (e.g. /usr/bin); should be used only in case of issues with GDAL processing;

: select a new temporary directory where temporary files are saved during processing; the path to the current temporary directory is displayed; default is a system temporary directory;
: reset to default temporary directory;